I've been going through the Blu-ray discs of The Persuaders! and watching that series for the first time. One of the bonus features on the set is an HD transfer of one episode of The Saint, "The Ex-King of Diamonds". It got me wondering why more of that show isn't on Blu-ray. I see there's another episode in HD ("The Queen's Ransom") on a Blu-ray called Retro-Action Volume 2, but that's it. It's a well-known show that seems like it would do well if released on Blu-ray or made available to stream in HD. Is there any particular reason that it hasn't been, when many other British shows from that era are available? My assumption here is that the color episodes were shot on film.